Related Articles

As one of the three essential macronutrients along with fats and proteins, carbohydrates probably constitute a fairly large portion of your diet. Even on low-carbohydrate plans, some carbs in the form of green, leafy vegetables are usually on the menu. Carbohydrates takes its name from two of the elements it contains: carbon and hydrogen. Along with oxygen, these elements comprise all carbohydrates, including sugars, starches, fiber and indigestible cellulose.

Carbohydrate Structure

Carbohydrates contain carbon, hydrogen and oxygen in a fixed ratio. For every one carbon atom, a carbohydrate contains one oxygen atom and two hydrogen atoms. Despite its simple chemical formulas, carbohydrates can have long, complex structures. Many form rings of carbon atoms, especially the simple sugars your body uses for energy. Scientists term small carbohydrate molecules monosaccharides, which means single sugar. Disaccharides consist of two simple monosaccharides joined together, and polysaccharides are the long, complex carbs that are most familiar as starches.

Simple Carbohydrates

Monosaccharides and disaccharides, also known as sugars, are simple carbohydrates. Your body expends little energy to convert these simple carbs into glucose, the sugar that fuels cellular activity. When you eat more sugar than you need, your body converts some of the excess energy into fat. The most common sugar, sucrose, is a disaccharide; another common disaccharide, lactose, is found in milk. Galactose and glucose together make lactose; if you're lactose-intolerant, it's because your body doesn't produce enough of the enzyme needed to split the disaccharide into its two monosaccharides.

Complex Carbohydrates

Polysaccharides, the complex carbohydrates, consist of hundreds or thousands of monosaccharide units linked together in long chains to form starches. Plants use these long-chain carbohydrate molecules for energy storage, which is why carbohydrates are most often concentrated in roots and tubers or in grain heads. The starch in grains is meant to fuel the growth of new seedlings. The human digestive system can process most starches, but fiber and cellulose, one of the structural components of wood, are indigestible.

Carbohydrates in Foods

Table sugar and complex carbohydrates in the form of starch both break down into their constituent simple sugars, but the process takes longer with some carbohydrates than with others. Sugars occur naturally in sweet foods such as fruits, honey and sugar cane. Most sugars have a sweet taste, unlike the long-chain complex carbohydrates that typically have a bland, neutral flavor. Foods high in starch include grains, legumes and root vegetables. Fiber is a special case among complex carbohydrates; although your body can't digest fiber, it needs it to keep your digestive system in good working order. Increase your fiber intake by choosing whole grains, eating whole fruits with skins and adding more legumes such as beans and lentils to your diet.

About the Author

Lauren Whitney covers science, health, fitness, fashion, food and weight loss. She has been writing professionally since 2009 and teaches hatha yoga in a home studio. Whitney holds bachelor's degrees in English and biology from the University of New Orleans.